Polyimide complex sheet

Abstract

A polyimide complex sheet is composed of an aromatic polyimide film, an intervening layer and a thin metal oxide layer in which the intervening layer is formed of a mixture of the metal oxide and the aromatic polyimide under such condition that a ratio of the metal oxide to the aromatic polyimide increases from a side facing the polyimide film to a side facing the metal oxide layer and the intervening layer is united to the polyimide film and the metal oxide layer under such condition that the metal oxide layer is not peelable from the polyimide film without breakage of the metal oxide layer.

1 . A polyimide complex sheet comprising an aromatic polyimide film and a thin metal oxide layer in which an intervening layer comprising a mixture of the metal oxide and the aromatic polyimide under such condition that a ratio of the metal oxide to the aromatic polyimide increases from a side facing the polyimide film to a side facing the metal oxide layer is arranged between the polyimide film and the metal oxide layer, the intervening layer being united to the polyimide film and the metal oxide layer under such condition that the metal oxide layer is not peelable from the polyimide film without breakage of the metal oxide layer.  
   
   
       2 . The polyimide complex sheet of  claim 1 , wherein the thin metal oxide layer has a thickness of 1 to 300 nm and the intervening layer has a thickness of 10 to 300 nm.  
   
   
       3 . The polyimide complex sheet of  claim 2 , wherein the polyimide film has a thickness of 3 to 200 μm.  
   
   
       4 . The polyimide complex sheet of  claim 1 , wherein the aromatic polyimide comprises an aromatic tetracarboxylic acid unit selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic acid unit, 2,3,3′,4′-biphenyltetracarboxylic acid unit, 3,3′,4,4′-benzophenonetetracarboxylic acid unit, 3,3′,4,4′-diphenylethertetracarboxylic acid unit, bis(3,4-dicarboxyphenyl)methane unit, 2,2-bis(3,4-dicarboxyphenyl)propane unit, pyromellitic acid unit, 1,4,5,8-naphthalenetetracarboxylic acid unit and 3,4,9,10-perylenetetracarboxylic acid unit, and an aromatic diamine unit selected from the group consisting of 4,4′-diaminobenzene unit, 4,4′-diaminodiphenyl ether unit, 3,3′-diaminodiphenyl ether unit, 2,2-bis[4-(4-aminophenoxy)phenyl]propane unit, 1,3-bis(3-aminophenoxybenzene) unit, 1,3-bis(4-aminophenoxybenzene) unit and dimethylphenylenediamine unit.  
   
   
       5 . The polyimide complex sheet of  claim 1 , wherein the metal oxide is silica.  
   
   
       6 . The polyimide complex sheet of  claim 1 , which has an elongation at break of 80% or higher based on an elongation at break of the aromatic polyimide film.  
   
   
       7 . The polyimide complex sheet of  claim 1 , which has an elongation at break of 15% or higher.  
   
   
       8 . The polyimide complex sheet of  claim 1 , which has an elastic modulus in tension of 80% or higher of an elastic modulus in tension of the aromatic polyimide film.  
   
   
       9 . The polyimide complex sheet of  claim 1 , which has an elastic modulus in tension of 4.5 GPa or higher.  
   
   
       10 . The polyimide complex sheet of  claim 1 , which has an elastic modulus in tension of 5.3 GPa or higher.  
   
   
       11 . A process for manufacturing a polyimide complex sheet of  claim 1 , which comprises the steps of: 
 preparing an aromatic polyimide precursor film comprising an aromatic polyamic acid and a polar organic solvent;    preparing a sol solution by hydrolyzing and condensing at least one metal-containing compound of the following formula:      R 1   n M(OR 2 ) m-n      in which R 1  is a non-hydrolyzable group, R 2  is a hydrocarbyl group having 1 to 5 carbon atoms, M is a metal atom, m is a valency of the metal atom, and n is an integer satisfying the condition of 0≦n<m-1, in an aqueous organic solvent;    coating the sol solution on the aromatic polyimide precursor film; and    heating the aromatic polyimide precursor film coated with the sol solution to convert the aromatic polyimide precursor film into an aromatic polyimide film.    
   
   
       12 . The process of  claim 11 , wherein the aromatic polyimide precursor film has an imidation ratio in the range of 8 to 50%.  
   
   
       13 . The process of  claim 11 , wherein the polar organic solvent is N,N-dimethylacetamide.  
   
   
       14 . The process of  claim 11 , wherein the aromatic polyimide precursor film comprises 20 to 40 wt. % of the polar organic solvent.  
   
   
       15 . The process of  claim 11 , wherein M in the formula is Si.  
   
   
       16 . The process of  claim 11 , wherein the sol solution contains the metal-containing compound in an amount of 0.1 to 5 wt. % in terms of a metal oxide content.  
   
   
       17 . The process of  claim 11 , wherein the aromatic polyimide precursor film comprises an aromatic tetracarboxylic acid unit selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic acid unit, 2,3,3′,4′-biphenyltetracarboxylic acid unit, 3,3′,4,4′-benzophenonetetracarboxylic acid unit, 3,3′,4,4′-diphenylethertetracarboxylic acid unit, bis(3,4-dicarboxyphenyl)methane unit, 2,2-bis(3,4-dicarboxyphenyl)propane unit, pyromellitic unit, 1,4,5,8-naphthalenetetracarboxylic acid unit and 3,4,9,10-perylenetetracarboxylic acid unit, and an aromatic diamine unit selected from the group consisting of 4,4′-diaminobenzene, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(3-aminophenoxybenzene), 1,3-bis(4-aminophenoxybenzene) and dimethylphenylenediamine.  
   
   
       18 . The process of  claim 11 , wherein the aqueous organic solvent comprises an hydrophilic organic solvent selected from the group consisting of alcohols, amides, ketones, and ethers.  
   
   
       19 . The process of  claim 11 , wherein the step for heating the aromatic polyimide precursor film coated with the sol solution is performed at a highest temperature in the range of 370 to 550° C.